Scientists have reported important results from an international clinical trial of a new drug targeting one of the most aggressive forms of breast cancer—triple-negative breast cancer (TNBC), according to HealthDay.

This type of cancer accounts for about 10–20% of cases, is more common in younger women, and is difficult to treat because it does not respond to hormone therapy and has limited responsiveness to immunotherapy. As a result, chemotherapy remains the standard treatment option, often with limited effectiveness.

The study tested a drug called datopotamab deruxtecan (Dato-DXd). It belongs to a class known as antibody-drug conjugates—often described as “smart chemotherapy.”

These drugs target cancer cells by binding to specific markers and delivering the drug directly into the tumor, while largely sparing healthy tissue.

The trial involved 644 patients with advanced or inoperable TNBC for whom immunotherapy was not an option.

Key results showed that:

  • Disease progression was delayed nearly twice as long compared to standard chemotherapy (10.8 months vs. 5.6 months);

  • Tumors shrank in 63% of patients versus 29% in the chemotherapy group;

  • Median overall survival was approximately 23.7 months.

In addition, the drug was better tolerated: side effects (such as nausea and mucosal inflammation) occurred but were less likely to lead to treatment discontinuation compared to conventional chemotherapy.

Researchers describe the findings as a significant step forward, as patients with this type of cancer previously had very few effective treatment options.

The drug is currently undergoing accelerated regulatory review, including by the FDA, and may become a new standard of care in the coming years.